they use local ingredients. when it comes to whipping up blackberries and cream and sicillian pistachio, what makes this different from a scoop of ice cream or a cup of frozen yogurt? we went to a chef for some answers. >> gelatto is a little bit lower in fat than regular ice cream. it is spun at a lower rate of speed so there is less what we call overrun in there. the air. >> reporter: less air means creamier and denser. ice cream by law is required to have 10% fat is made with cream and sugar and is spun faster than gelatto so there is more air in it. then there's frozen custard. frozen custard, the trick is? >> egg yolk. >> reporter: it has a higher fat content because of egg yolks. what about frozen yogurt? that is made with milk, how does it get its signature tangy taste? >> yogurt is a cultured milk product. >> reporter: if you are trying to avoid dairy, check out sorbet, commonly sold at gelatto shops. it is made with sugar, water and flavoring. >> it is good. >> reporter: of these five frozen summer favo